In emulsion polymerization, non-copolymerizable surfactants (or emulsifiers) have been conventionally employed to emulsify reactants. While functional monomers, such as, for example, reactive carboxylic acids, like acrylic acid, sodium styrene sulfonate, 2-sulfoethyl methacrylate, and the like, have heretofore been used to impact stability to polymers made by emulsion polymerization, such monomers are not of themselves emulsifiers, and they contribute stability to a product polymer only after becoming part of the growing polymer molecule in a polymerization reaction. Such monomers must usually be used in an emulsion polymerization reaction in the presence of relatively large amounts of noncopolymerizable surfactants, which can themselves be undesirable. In the art of producing stable and useful free radical induced polymers dispersed in water preformed surfactants are employed for the intended purpose of emulsion polymerization. The surfactants heretofore in common use apparently do not become chemically reacted into a product polymer molecule by carbon to carbon bonding (as distinct from some sort of physical mixing, adsorbing, or the like).
Surfactants containing sulfonate groups, are, of course, known, but, so far as now known to me, these materials are apparently not chemically reactive so as to be incorporated by emulsion polymerization directly into an emulsion polymerized product polymer because of inherent molecular structural considerations. The art seems to have experienced problems in introducing into a molecule having true surfactant properties both a sulfonate (as distinct from a sulfate) group and a reactive ethylenic double bond. Problems have also been experienced in the art in preparing such reactive surfactant molecules in a concentrated, high-purity form, such as would be necessary, or desirable, for example, for many commercial scale emulsion polymerization reactions wherein such reactive surfactants would be useful.